Original Research

The potential of the pinhole as a visual aid in the developing world

Antony S. Carlson, Warren A. Carlson, William F. Harris
African Vision and Eye Health | Vol 75, No 1 | a318 | DOI: https://doi.org/10.4102/aveh.v75i1.318 | © 2016 Antony S. Carlson, Warren A. Carlson, William F. Harris | This work is licensed under CC Attribution 4.0
Submitted: 26 June 2015 | Published: 04 August 2016

About the author(s)

Antony S. Carlson, Department of Optometry, University of Johannesburg, South Africa
Warren A. Carlson, National Institute for Theoretical Physics, University of the Witwatersrand, South Africa
William F. Harris, Department of Optometry, University of Johannesburg, South Africa


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Abstract

Purpose: Providing vision correction in communities where healthcare facilities are unavailable is problematic. Here, we explore the possibility of using pinholes as near visual aids in the developing world.

Method: Uncompensated (without the pinhole) proximal visual acuities (VAs) were measured and recorded for one eye of 45 presbyopic subjects over the age of 50 years in photopic (250 lux) and scotopic (20 lux) conditions. The proximal VAs were then repeated while the subjects looked through nine different pinholes.

Results: The VAs varied with the diameter of each pinhole. A comparative measure was devised to determine the relative performance of different diameter pinholes as a near visual aid. The results suggest an improvement of more than 40% in VA in about 67% of subjects in good lighting conditions and about 60% in poorer lighting conditions.

Conclusion: By creating more awareness that there are other ways of improving vision that cost almost nothing, visual impairment can be reduced until spectacles become available.


Keywords

pinhole; visual acuity; minimum angle of resolution

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